src/libs/bsd/fgetln.c

   1 /*
   2  * Copyright 2006, Haiku, Inc. All Rights Reserved.
   3  * Distributed under the terms of the MIT License.
   4  *
   5  * Authors:
   6  *              Axel Dörfler, axeld@pinc-software.de
   7  */
   8
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13
  14
  15 #define LINE_LENGTH 4096
  16
  17
  18 char *
  19 fgetln(FILE *stream, size_t *_length)
  20 {
  21         // TODO: this function is not thread-safe
  22         static size_t sBufferSize;
  23         static char *sBuffer;
  24
  25         size_t length, left;
  26         char *line;
  27
  28         if (sBuffer == NULL) {
  29                 sBuffer = (char *)malloc(LINE_LENGTH);
  30                 if (sBuffer == NULL)
  31                         return NULL;
  32
  33                 sBufferSize = LINE_LENGTH;
  34         }
  35
  36         line = sBuffer;
  37         left = sBufferSize;
  38         if (_length != NULL)
  39                 *_length = 0;
  40
  41         for (;;) {
  42                 line = fgets(line, left, stream);
  43                 if (line == NULL) {
  44                         free(sBuffer);
  45                         sBuffer = NULL;
  46                         return NULL;
  47                 }
  48
  49                 length = strlen(line);
  50                 if (_length != NULL)
  51                         *_length += length;
  52                 if (line[length - 1] != '\n' && length == sBufferSize - 1) {
  53                         // more data is following, enlarge buffer
  54                         char *newBuffer = realloc(sBuffer, sBufferSize + LINE_LENGTH);
  55                         if (newBuffer == NULL) {
  56                                 free(sBuffer);
  57                                 sBuffer = NULL;
  58                                 return NULL;
  59                         }
  60
  61                         sBuffer = newBuffer;
  62                         sBufferSize += LINE_LENGTH;
  63                         line = sBuffer + length;
  64                         left += 1;
  65                 } else
  66                         break;
  67         }
  68
  69         return sBuffer;
  70 }
  71